1) Prove that if A⊨tautB and C⊨tautD then A∨C⊨tautB∨D . 2) Show that the formulae A≡⊥ and ¬A are tautologically equivalent.

You have 138.72 in your saving account u take out 45.23 and 18.00 you deposit 75.85 into your account

Formulate alisha has a number in mind. if she adds three to her number the result is less than five. use this information to write and solve an inequality about alisha's number. then graph the solution set.

Julie buys 2kg of apples and 7kg of pears ? 12.70. the pears cost ? 1.30 per kilogram what is the price per kilogram of the apples? show your working out